[DeTomaso] Lexan windshields and door glass

[JDeRyke at aol.com]

I looked into this a year or so ago for wt savings. Unless the law in your 
State law has recently changed, front windshields in anything but safety 
glass are not DOT-legal (reason is, in a crash, rescue crews may not be able to 
break your lexan windshield to pull you out before fire swallows the whole 
car), so these may be racecar-only. I had one intended for speedboats on a 
fiberglas roadster I built many years ago, and I had mucho trouble getting 
the thing registered (in CA). 
Lexan (polycarbonate) does in fact make a good windshield or door side 
windows, as verified by the U.S Air Force which uses Lexan in its fighter plane 
canopies & some helmet shields. But that special Lexan has a proprietary 
coating on at least its outside for abrasion resistence and is definitely not 
cheap. 2-side-coated Lexan doesn't tint. It needs to be thick enough to not 
buckle under wind pressure at high speeds as its less stiff than glass. A raw 
piece of hard-coated polycarbonate big/thick enough for a windshield is 
roughly $500. The coated stuff does apparently hold up to moderate wiper and 
door-fuzzy abrasion according to some racecar & boat guys, but not nearly as 
well as safety glass. It hazes & yellows over time (think of your Lexan 
plastic headlight lenses) so you need to buff it out with fine polishing compound 
now & then. I checked with Larry Stock's plastics company 6 months ago and 
he doesn't have a close-control high-temp oven big enough to make door 
windows and especially not windshields of even uncoated Lexan. The DOT are less 
concerned with side & back windows.
For back windows and front/rear 1/4 windows, I've been using tinted 
plexiglas (polyacrylic) for about 12 years, which has a low forming temp of only 
about 140F (about 1/2 that of Lexan) and is much weaker than Lexan. With 
plexi, you want the type that has lots of UV-absorbers built in, or your quarter 
windows will sun-craze in a year or less. The back window is well shielded 
so its less apt to craze. Plexi home-tints easily with Rit dye in hot water, 
just like your optometrist tints your acrylic sunglasses. FWIW- J Deryke